Is it possible to get another application's primary color like lollipop's recents view

Question

I found

http://developer.android.com/reference/android/app/ActivityManager.html#getRunningTasks(int)

to retrieve current application's baseActivity or topActivity. Then I was able to get the Activity's Resources object.

However, the api is no longer available to third party applications in Lollipop

Answer 1

You can retrieve the launcher Intent for an application using PackageManager.getLaunchIntentForPackage and PackageManager.getActivityInfo will return the ActivityInfo for it.

Once you have that information you can create a new Theme, then use the resources from PackageManager.getResourcesForApplication to retrieve the attrs needed to find the colorPrimary value.

    try {
        final PackageManager pm = getPackageManager();

        // The package name of the app you want to receive resources from
        final String appPackageName = ...;
        // Retrieve the Resources from the app
        final Resources res = pm.getResourcesForApplication(appPackageName);
        // Create the attribute set used to get the colorPrimary color
        final int[] attrs = new int[] {
                /** AppCompat attr */
                res.getIdentifier("colorPrimary", "attr", appPackageName),
                /** Framework attr */
                android.R.attr.colorPrimary
        };

        // Create a new Theme and apply the style from the launcher Activity
        final Theme theme = res.newTheme();
        final ComponentName cn = pm.getLaunchIntentForPackage(appPackageName).getComponent();
        theme.applyStyle(pm.getActivityInfo(cn, 0).theme, false);

        // Obtain the colorPrimary color from the attrs
        TypedArray a = theme.obtainStyledAttributes(attrs);
        // Do something with the color
        final int colorPrimary = a.getColor(0, a.getColor(1, Color.WHITE));
        // Make sure you recycle the TypedArray
        a.recycle();
        a = null;
    } catch (final NameNotFoundException e) {
        e.printStackTrace();
    }

One caveat is that the launcher Activity may not contain a theme attribute, in which case you may consider using PackageManager.getApplicationInfo, but there's no guarantee the Application tag contains a theme attribute as well.

Here are some examples:

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